Subject: Re: [AUDITORY] Localizing smoke detectors - why is it so hard? From: "robertbaumgartner@xxxxxxxx" <robertbaumgartner@xxxxxxxx> Date: Tue, 25 Jun 2013 12:33:10 +0200 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--Apple-Mail=_F90A4BA1-CB05-4C5A-AF19-A69BEAD7355D Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 Dear Jennifer Groh, when localizing smoke detectors, localization of the horizontal = direction (left/right) of the sound source based on ITD/ILD should work = fine. However, localization in vertical or, more precisely, sagittal = planes relies on spectral cues. So, if a smoke detector emits chirps = with relatively long cycle duration, a listener perceives rather = fluctuating source elevation, known as directional bands, than a stable = elevation. Latter would require a broadband spectral profile at a = certain time instance. Moreover, localization performance in sagittal planes deteriorates with = increasing sensation level, known as negative level effect. Thus, if the = smoke detecter is very loud this does not help for localizing it. Hope this helps you. If you need detailed references for what I've = stated above, don't hesitate to contact me... All the best, Robert ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Robert Baumgartner Psychoacoustics and Experimental Audiology Acoustics Research Institute Austrian Academy of Sciences Wohllebengasse 12-14, 1040, Wien ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Am 25.06.2013 um 10:46 schrieb Jennifer M. Groh <jmgroh@xxxxxxxx>: > Dear List, >=20 > I am writing a book for a general audience on how the brain processes = spatial information ("Making Space"). The chapter on hearing covers many = topics in sound localization, but there is one that I'm currently still = quite puzzled about: why it is so hard to localize a smoke detector when = its battery starts to fail? Here is what I have considered so far: >=20 > - To my ear, the chirp sounds high frequency enough that ILD cues = should be reasonably large. >=20 > - At the same time, it seems to have a broad enough bandwidth, and in = any case it has onset-and-offset cues, that ITD cues should be usable. >=20 > - A possibility is that the chirp is too brief, and that limits = dynamic feedback, i.e. changes in ITD and ILD as the head turns during a = sound. However, in my laboratory we have obtained excellent sound = localization performance in head-restrained monkeys and human subjects = localizing sounds that are briefer than the reaction time to make an = orienting movement. >=20 > - An additional possibility is that we have too little experience with = such sounds to have assembled a mental template of the spectrum at the = source, so that spectral cues are of less use than is normally the case. >=20 > I'm leaning towards a combination of the last two factors, which = together would render the cone of confusion unresolved for these = stimuli. >=20 > Thoughts? >=20 > Best wishes, >=20 > --Jennifer Groh >=20 > --=20 > Jennifer M. Groh, Ph.D. >=20 > Professor > Department of Psychology and Neuroscience > Department of Neurobiology > Center for Cognitive Neuroscience >=20 >=20 > B203 LSRC, Box 90999 > Durham, NC 27708 >=20 > 919-681-6536 > www.duke.edu/~jmgroh --Apple-Mail=_F90A4BA1-CB05-4C5A-AF19-A69BEAD7355D Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=iso-8859-1 <html><head><meta http-equiv=3D"Content-Type" content=3D"text/html = charset=3Diso-8859-1"></head><body style=3D"word-wrap: break-word; = -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; = "><div>Dear Jennifer Groh,</div><div><br></div><div>when localizing = smoke detectors, localization of the horizontal direction (left/right) = of the sound source based on ITD/ILD should work fine. However, = localization in vertical or, more precisely, sagittal planes relies on = spectral cues. So, if a smoke detector emits chirps with relatively long = cycle duration, a listener perceives rather fluctuating source = elevation, known as directional bands, than a stable elevation. Latter = would require a broadband spectral profile at a certain time = instance.</div><div>Moreover, localization performance in sagittal = planes deteriorates with increasing sensation level, known as negative = level effect. Thus, if the smoke detecter is very loud this does not = help for localizing it.</div><div><br></div><div>Hope this helps you. If = you need detailed references for what I've stated above, don't hesitate = to contact me...</div><div><br></div><div>All the = best,</div><div>Robert</div><br><div apple-content-edited=3D"true"> <div style=3D"color: rgb(0, 0, 0); font-family: Helvetica; font-size: = medium; font-style: normal; font-variant: normal; font-weight: normal; = letter-spacing: normal; line-height: normal; orphans: 2; text-align: = -webkit-auto; text-indent: 0px; text-transform: none; white-space: = normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; = -webkit-text-stroke-width: 0px; word-wrap: break-word; = -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div = style=3D"color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; = font-style: normal; font-variant: normal; font-weight: normal; = letter-spacing: normal; line-height: normal; orphans: 2; text-align: = -webkit-auto; text-indent: 0px; text-transform: none; white-space: = normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; = -webkit-text-stroke-width: 0px; word-wrap: break-word; = -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; = "><div><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; = -webkit-line-break: after-white-space; "><span style=3D"background-color: = rgb(255, 255, 255); ">~~</span><span style=3D"background-color: rgb(255, = 255, 255); ">~~</span><span style=3D"background-color: rgb(255, 255, = 255); ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span><span style=3D"background-color: rgb(255, 255, 255); = ">~~</span></div><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: = space; -webkit-line-break: after-white-space; "><a = href=3D"http://www.kfs.oeaw.ac.at/index.php?option=3Dcom_content&view=3D= article&id=3D658:baumgartner-di-robert&catid=3D13&Itemid=3D419= &lang=3Den">Robert Baumgartner</a><br style=3D"background-color: = rgb(255, 255, 255); "><span style=3D"background-color: rgb(255, 255, = 255); ">Psychoacoustics and Experimental Audiology</span><br = style=3D"background-color: rgb(255, 255, 255); "><a = href=3D"http://www.kfs.oeaw.ac.at"></a><a = href=3D"http://www.kfs.oeaw.ac.at/" style=3D"background-color: rgb(255, = 255, 255); ">A</a>coustics Research Institute<br = style=3D"background-color: rgb(255, 255, 255); ">Austrian Academy of = Sciences<br style=3D"background-color: rgb(255, 255, 255); "><span = style=3D"background-color: rgb(255, 255, 255); ">Wohllebengasse 12-14, = 1040, Wien</span></div><div style=3D"word-wrap: break-word; = -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); ">~~</span><span = style=3D"background-color: rgb(255, 255, 255); = ">~~</span></div></div><div><br></div></div><br = class=3D"Apple-interchange-newline"></div><br = class=3D"Apple-interchange-newline"><br = class=3D"Apple-interchange-newline"> </div> <br><div><div>Am 25.06.2013 um 10:46 schrieb Jennifer M. Groh <<a = href=3D"mailto:jmgroh@xxxxxxxx">jmgroh@xxxxxxxx</a>>:</div><br = class=3D"Apple-interchange-newline"><blockquote type=3D"cite">Dear = List,<br><br>I am writing a book for a general audience on how the brain = processes spatial information ("Making Space"). The chapter on hearing = covers many topics in sound localization, but there is one that I'm = currently still quite puzzled about: why it is so hard to localize a = smoke detector when its battery starts to fail? Here is what I = have considered so far:<br><br>- To my ear, the chirp sounds high = frequency enough that ILD cues should be reasonably large.<br><br>- At = the same time, it seems to have a broad enough bandwidth, and in any = case it has onset-and-offset cues, that ITD cues should be = usable.<br><br>- A possibility is that the chirp is too brief, and that = limits dynamic feedback, i.e. changes in ITD and ILD as the head turns = during a sound. However, in my laboratory we have obtained = excellent sound localization performance in head-restrained monkeys and = human subjects localizing sounds that are briefer than the reaction time = to make an orienting movement.<br><br>- An additional possibility is = that we have too little experience with such sounds to have assembled a = mental template of the spectrum at the source, so that spectral cues are = of less use than is normally the case.<br><br>I'm leaning towards a = combination of the last two factors, which together would render the = cone of confusion unresolved for these = stimuli.<br><br>Thoughts?<br><br>Best wishes,<br><br>--Jennifer = Groh<br><br>-- <br>Jennifer M. Groh, = Ph.D.<br><br>Professor<br>Department of Psychology and = Neuroscience<br>Department of Neurobiology<br>Center for Cognitive = Neuroscience<br><br><br>B203 LSRC, Box 90999<br>Durham, NC = 27708<br><br>919-681-6536<br><a = href=3D"http://www.duke.edu/~jmgroh">www.duke.edu/~jmgroh</a><br></blockqu= ote></div><br></body></html>= --Apple-Mail=_F90A4BA1-CB05-4C5A-AF19-A69BEAD7355D--